Do you know the three typical symptoms of eczema?

Author: Zhang Jianzhong, Chief Physician, Peking University People's Hospital

The 13th Chairman of the Chinese Medical Association Dermatology and Venereology Branch

Reviewer: Wang Aiping, Chief Physician, Peking University First Hospital

Each of us should have experienced some skin discomfort symptoms to a greater or lesser extent, which may be redness, itching, or some small rashes. In clinical practice, there is one skin disease that is particularly common, and that is eczema.

I believe everyone is familiar with the name of eczema, but do you know what kind of skin manifestations are eczema? How should we distinguish eczema from other diseases? This article will answer your questions.

1. What symptoms may indicate eczema?

Eczema is actually very easy to detect because its skin lesions and symptoms are usually obvious and can be easily observed by us:

① Itching and pain.

Regardless of the cause of eczema, it usually manifests as a certain amount of itching. This itching can be mild or severe. If it is ordinary eczema, the itching is generally tolerable, but there is also a type of atopic dermatitis, also called atopic eczema, in which the itching symptoms are more severe. Some people even cannot sleep at night due to the itching, and cannot study or work during the day.

The time when the itching symptoms of eczema appear is usually related to the cause. For example, if it is solar dermatitis eczema, it will generally cause itching after exposure to sunlight, and in some cases it will also cause pain.

② Erythema and papules.

In terms of skin manifestations, we often see some local redness, which we call erythema, or some small particles grow locally, rice, millet, mung bean-sized bumps, which we call papules. If these papules fuse together to form a thick piece, we call it a plaque. If the erythema is relatively large, it can also be called a patch.

Since these skin lesions are often itchy, people may form some scratches after scratching. Some people may even form blood scabs if they scratch more vigorously. Therefore, in patients with more severe symptoms, we often see erythema, papules, scratches, and blood scabs coexisting.

③ Exudation.

In addition to erythema, papules, scratches and blood scabs, if the symptoms are more severe, exudation may also occur, which in layman's terms means "water" flowing.

Of course, the above three points are just some common features of various types of dermatitis and eczema. In addition, different types of dermatitis and eczema may have their own other characteristics.

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2. What diseases should we pay attention to distinguish eczema from?

There are some diseases whose symptoms are very similar to those of eczema, so they are often misdiagnosed and mistreated. In order not to delay the disease and to carry out targeted treatment early and effectively, we must pay attention to distinguishing these diseases from eczema.

④ Scabies.

Let me give you a real example. A patient came to the hospital for treatment many times. Each time, the doctor diagnosed him with allergic dermatitis, or allergic eczema. He used targeted hormone drugs. Despite repeated dressing changes, his condition did not improve. It was not until the author saw the patient and asked him to take off his clothes to fully expose himself that he found that dermatitis also appeared in the perineum and between his fingers. After checking the fingers, he found that the scabies test was positive. Only then did he know that the patient actually had scabies. Scabies is an infectious disease. After adjusting the medication and symptomatic anti-infection treatment, he recovered quickly.

⑤ Immune diseases.

Some people have congenital diseases, or immune diseases, which can cause skin damage and may be confused with eczema. For example, some children have symptoms similar to eczema, but if you look at the large range of motion of their fingers, they may have hyperextension of the joints. There are also some children, who are only seven or eight years old, but have many acne-like cysts on their faces, their skin is very dry, and they are prone to colds. After blood tests, it was found that the immunoglobulin E in his blood was greater than 2500, while that of ordinary people is generally less than 100. Finally, it was discovered that it was a gene mutation and immune problems, and it was finally diagnosed as high IgE syndrome.

⑥ Systemic diseases.

There are real cases like this in clinical practice. The skin manifestations are similar to eczema, but after blood tests, it was found that there were atypical lymphocytes, and it was finally diagnosed as lymphoma.

The above cases show that differential diagnosis between eczema and other diseases is indeed very important. In order to avoid misdiagnosis and mistreatment, what methods can help us make judgments in clinical practice?

3. What tests can help us diagnose eczema?

First of all, we need to make a basic judgment based on the patient's specific manifestations, such as whether the skin lesions occur in a location that is easily exposed to the sun, or whether they occur in a certain season, or after approaching or contacting a certain substance. At this time, we can preliminarily judge some possible causes.

If we are unable to determine, we can do some further tests, such as checking for suspected allergens, such as hair dye, nickel, fragrances, and spices.

The most common method in clinical practice is the patch test, which is to put about 20, 40 or 60 suspected allergens together in a small container, with each substance occupying only a small area, and then label them and stick them on the normal skin on the back. After 48 hours of observation, peel them off to see which part is red and damaged, and then determine the suspected allergen that has been exposed to the corresponding contact.

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Sometimes, some substances will undergo photochemical reactions after being exposed to ultraviolet rays, so sometimes after applying the patch, it is necessary to irradiate with ultraviolet rays and observe for 48 hours or 72 hours.

In addition, if it is not a contact allergy, you can also do an allergen test by drawing blood to determine whether there is an inhalation or food allergy, and to see if there are any special autoantibodies.